2. The sniper rifle with the Ammo Increase, Damage Increase and either the Reload Speed or Rate of Fire upgrades (Laser Targeting would help but not really necessary since you have a scope)

And, of course, not to mention at least one EMP 'nade to toss at the big bot when it arrives.

On a recent playthrough, I discovered how brutally effective the revolver is with these three upgrades applied. Makes quick work of the mercs, even at a considerable distance, yet takes up far less inventory space** than the sniper rifle. Check it out.

Tbh it's probably even easier with non-lethal taken downs and stun gun. You can easily run and high jump around the map taking everyone out this way in no time at all. Just have a few protein bars ready and work your way anti-clockwise from where you start.

What do you mean it's "probably" easier? Have you tried your own method?

This particular achievement is time-sensitive, as you know, meaning the clock is running. The method I used and described above should allow a player the greatest number of kills in the least amount of time, for a relatively easy achievement.

My bad, my post was a bit vague and not useful. I saved Malik the first time getting my ghost and non lethal achievements, and on subsequent lethal playthroughs I found it harder as you attract attention. My approach was quick and silent, but it depends heavily on augs and take downs.

Cloak is obviously very helpful as is upgraded sprint. Activated both and made my way to the right building, jumped up and KO'd the two guards. Threw an EMP grenade for the robot and then took out the two (I think 2) heavies at the back with the stun gun from behind. Moped up any soldiers near the back then moved into the adjacent building for the snipers. Then took out the final heavy near the chopper.

I personally found this approach very quick and easier (as I obviously don't get shot) than on any of my lethal playthroughs. But perhaps I will try your method next time, I really do like the revolver with exploding rounds but I find the sniper rifle takes up far too much room versus how many times I actually use it.

Edit: Although tbh I think once the robot and heavies are dealth with, you could take your time? I guess they do the most damage.

Hey, good advice. Yeah, I found out, too, that the heavies need to be neutralized first, since they're pouring out so much more lead. Particularly what you don't want is for one of them to make his way to the other side of the VTOL. That's when I think Mailk's damage meter starts moving into redline territory... So, a laser-targeting revolver with those great exploding bullets takes both down almost immediately. Then the standard rifle shooters. Then the bot with an EMP (before it can start firing). Then the snipers. Done.

I also agree that carrying the sniper rifle around (or the rocket launcher, for that matter) prior to this part of the campaign is a real handicap. But, I brought it along, if nothing less, for insurance, anyway. After this, it's really not needed. Too bad I you can't sell it at that point...LOL

A further note about the enhanced revolver: be careful about using it around civilians. The splash damage radius from the explosion is enough to kill anything within 4 or 5 feet. Not that there's any penalty for this, but, hey, we want to be professional, right?